LED5000PHR STMicroelectronics, LED5000PHR Datasheet - Page 40

• Manufacturer Part Number: LED5000PHR
• Description: Current & Power Monitors & Regulators 3A monolithic Conv 850kHz Synch
• Manufacturer: STMicroelectronics

Specifications of LED5000PHR

• Rohs: yes
• Product: Current Regulators
• Supply Voltage - Max: 48 V
• Supply Voltage - Min: 5.5 V
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Package / Case: HPSO-8
• Accuracy: +/- 3 %
• Input Voltage Range: 5.5 V to 48 V
• Output Current: 23 uA
• Sensing Method: High or Low Side
• Supply Current: 1.7 mA

Application notes - alternative topologies
6.3
40/51
In case of open row, the positive output voltage tends to diverge, exceeding the D3
maximum reverse voltage and so the diode would be damaged. The overvoltage protection
limits V
The network D4, R8 implements a level shifter to drive the gate of the transistor Q1. The
voltage at Q1 is:
Equation 64
Considering the V
Equation 65
the gate is driven inside the component specification. R8 can be dimensioned to discharge
the gate when V
In case the input voltage range of the application is not suitable to implement a level shifter
to drive Q1, a dissipative clamping network (like R5, D6) must be used.
To design the compensation network for the positive buck-boost topology please refer to
paragraph
Floating boost
The floating boost topology (see
range narrower than the output voltage, that is the voltage drop across the LEDs and the
sensing resistor (i.e. V
referred to V
LEDs.
Figure 30. Floating boost
The device is supplied by the output voltage so the maximum voltage drop across the LEDs
string is 48 V. The direct path of the boost conversion (C
proper startup when the input voltage is:
OUT
Chapter 6.4: Compensation network design for alternative topologies
and it protects the power components in case of load disconnection.
IN
and not GND, but this is typically suitable for a floating load like a string of
V
SW
IN
IN
is low.
range 18 to 30 V:
IN
V
V
Q1 GATE MAX
< V
Q1 GATE MIN
OUT
V
Q1 GATE
Doc ID 023951 Rev 1
). The topology is called floating since the output voltage is
LX
V
Figure 30
CC
=
=
=
V
V
V
SW
SW
SW
) serves those applications with an input voltage
–
–
–
V
V
V
DZ4
DZ4
DZ4
=
=
V
GND
=
30V 16V
18V 15V
REF
V
SW
–
OUT
–
–
15V
, V
=
DIODE
=
15V
3V
, L) guarantees the
.
LED5000
AM13514v1